title: Cerebral magnetic resonance spectroscopy at 7 Tesla: standard values and regional differences.
abstract: OBJECTIVE
  At lower magnetic field strengths, regional differences of cerebral metabolite distributions have been described, but these data are controversial. Magnetic resonance spectroscopy at 7 T is expected to deliver high spectral resolution and good differentiation, but there are problems arising at high magnetic field strengths that may diminish spectral quality. Because there have been only a few studies in humans so far, there are no standard values for 7 T concerning regional metabolite distributions and concentrations.
  
  
  METHODS
  In the present study, the metabolites detectable with (1)H magnetic resonance spectroscopy, N-acetyl-aspartate, choline, and creatine (Cr), were evaluated with a single-voxel sequence. Five voxels were placed in the frontal and parietal white matter and the insular, thalamic, and occipital gray matter.
  
  
  RESULTS
  For N-acetyl-aspartate, the lowest values were found in frontal white matter and the highest in thalamic gray matter. Choline displayed the lowest values in frontal white matter and the highest in insular gray matter. Cr showed the lowest values in frontal white matter and the highest in thalamic gray matter. The highest ratio of choline to Cr was found in parietal white matter and the lowest in thalamic gray matter. The highest ratio of N-acetyl-aspartate to Cr was found in thalamic gray matter and the lowest in frontal white matter.
  
  
  CONCLUSIONS
  In the present study, regional cerebral metabolite differences were verified with high-field magnetic resonance spectroscopy. Quantitative values and metabolite ratios could be a basis for further clinical studies.
authors.affiliation: Department of Neuroradiology, University Hospital Giessen and Marburg, Justus Liebig University Giessen, Germany. astrid.e.grams@radiol.med.uni-giessen.de
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Grams
authors.forename: Irina
authors.initials: I
authors.lastname: Brote
authors.forename: Stefan
authors.initials: S
authors.lastname: Maderwald
authors.forename: Kiriaki
authors.initials: K
authors.lastname: Kollia
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
authors.forename: Michael
authors.initials: M
authors.lastname: Forsting
authors.forename: Elke R
authors.initials: ER
authors.lastname: Gizewski
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D002540:Cerebral Cortex / Q000737:chemistry / Q000000981:diagnostic imaging*; D002794:Choline / Q000737:chemistry*; D003401:Creatine / Q000737:chemistry*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D011859:Radiography; D012015:Reference Standards
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline